In auger-type snow plows, an auger housing is mounted to a vehicle body frame including travel device, such that the auger housing can be raised and lowered and made to roll. The auger housing includes an auger. An auger snow plow can scrape up snow by means of a front auger while traveling forward, and can disperse the scraped up snow far away by means of a blower via a shooter.
A snow plow including an auger employs a system for varying the height of the auger housing in accordance with the conditions of the snow plowing work. It is more efficient to move the snow plow when the bottom surface of the auger housing has been raised. It is more efficient to plow snow when the bottom surface of the auger housing has been lowered. The height of the auger housing is also often varied according to unevenness in the road surface when snow is plowed.
It is highly inconvenient for a worker to make these variations to the height of the auger housing through manual labor. To alleviate the burden on the worker, the bottom surface of the auger housing can be raised and lowered with a power assist. This feature is disclosed in Japanese Utility Model Application Laid-Open Publication No. 63-136012 (JP-U-S63-136012) and Japanese Patent Application Laid-Open Publication No. 2007-032218 (JP-A-2007-032218).
In the snow plow disclosed in JP-U-S63-136012, the auger housing angle is used to control an angle of inclination detector provided to the auger housing to detect the angle of the auger housing relative to the direction of gravity.
In the snow plow taught in JP-A-2007-032218, the raised/lowered angle of the auger housing is controlled due to the angle of the auger housing relative to a travel frame having the travel device being detected by a height position sensor. When a reset switch is turned on by a worker, a control unit controls a raising/lowering drive mechanism so as to adjust the auger housing to a predetermined height reference position. The term “height reference position” refers to a position where the bottom end of a scraper included in the auger housing comes in contact with a flat surface (the traveled road surface) while the auger housing is in a horizontal state.
For example, when the travel device is traveling forward over an inclined surface; i.e., when the front is raised, the auger housing lowers so as to be horizontal. At this time, the auger housing could possibly come in contact with the upward inclined surface before becoming horizontal. The raising/lowering drive mechanism continues driving in order to make the auger housing horizontal. There is yet room for improvement in increasing the travel performance of the snow plow as well as increasing the durability of the snow plow.
In view of this, there is demand for a feature whereby travel performance and durability of the snow plow are increased.